PORTLAND, Maine — A teeth-chattering cold wave with sub-zero temperatures was expected to keep its icy grip on much of the eastern U.S. into the weekend before seasonable temperatures bring relief. A polar air mass that’s been blamed for multiple deaths in the Midwest moved into the Northeast on Wednesday, prompting the National Weather Service to issue wind chill warnings across upstate New York and northern New England. In northern Maine, the temperature dipped to as low as 36 below zero Wednesday morning. The weather service was calling for a wind chills as low as minus-45. Keith Pelletier, the owner of Dolly’s Restaurant in Frenchville, said his customers were dressed in multiple layers of clothing and were keeping their cars running in the parking lot while eating lunch. It’s so cold that even the snowmobilers are staying home, he said.“You take the wind chill at 39 below and take a snowmobile going 50 mph, and you’re about double that,” he said. “That’s pretty cold.”The Canadian air mass that brought arctic air is being blamed for several deaths across the Midwest. It also forced schools to close, caused delays of commuter trains and subways, and kept plumbers busy with frozen pipes.In New York City, food vendor Bashir Babury contended with bone-numbing cold when he set up his cart selling coffee, bagels and pastries at 3 a.m. Wednesday. On the coldest of days, he wears layers of clothing and cranks up a small propane heater inside his cart. “I put on two, three socks, I have good boots and two, three jackets,” he said. “A hat, gloves, but when I’m working I can’t wear gloves.” In Pottsville, Pa., letter carrier Cheryl Vandermeer was stoic as she walked her route Wednesday with temperatures in the teens and wind chill in the single digits. She was thankful she had a job that kept her moving, even if it was outside.“I’m not just standing around,” she said. “So for me it’s cold, but it’s not intolerable.”————Associated Press writers Karen Matthews in New York City and Michael Rubinkam in Pennsylvania contributed to this report.